1. Field of the Invention
This invention relates to a method of treatment of sickle cell anemia and a compound having properties which resist sickling of hemoglobin in a sickle cell anemia patient.
2. Description of the Prior Art
Sickle cell anemia is a hereditary blood disease which afflicts members of the Negro race and, to a very limited extent, Caucasians of Mediterranean and mideastern ancestry. The anemia results from the physical aggregation of the hemoglobin protein constituent in red blood cells. This aggregation results in a distortion in shape of deoxygenated red blood cells and causes impairment of flow of the blood through the capillaries (sickle cell "crises"). As the principal function of hemoglobin is to transport oxygen from the lungs to body tissues, efficient flow of oxygen throughout the body's tissues is impeded by the anemia due to a lower number of red blood cells. Sickle cell anemia also may have an indirect effect on the heart, lungs, kidneys, spleen, hips and brain. Sickle cell anemia crises can be extremely painful, can result in infections such as pneumonia, can result in skin ulceration, can contribute to strokes and seizures in the one afflicted and can also result in the development of chronic bone infections.
In general, the result of the differences between cells containing hemoglobin A, the normal hemoglobin, and hemoglobin S, the sickle cell hemoglobin, is that the former cell is generally flexible and bioconcave discoid in shape while the latter is more rigid and crescent shaped and typically has pointed ends. This rigidity and distortion in shape cause the cells to be lodged in the capillary. Hemoglobin molecules contain two beta polypeptide chains and two alpha polypeptide chains. In the sickle cell hemoglobin, a mutation is present in the beta chains. More specifically, the sixth amino acid of each beta chain is changed from glutamic acid to valine. As a result of this mutation, hemoglobin S upon deoxygenation polymerizes and causes the cell to assume the elongated, sickle-like configuration. As the sickle cells have a much shorter life span than normal red cells, the effect on the body is to deplete the total volume of blood cells thereby creating an anemic condition.
To the best of applicant's knowledge there has been no known effective means of arresting sickle cell anemia so as to prevent an individual who has this malady from experiencing one of the above-described problems. One known laboratory test employed in diagnosing sickle cell anemia is the performance of a hemoglobin electrophoresis test which is used to determine whether an individual has sickle cell anemia (homozygous) or merely the sickle cell trait (heterozygous), with the latter referring to an individual not having the disease but having the capability of transmitting the disease to offspring if mated to another heterozygote. Treatment for the various complications which have resulted from sickle cell anemia are known and should be distinguished from prophylactic activity (unknown) which would resist the occurrence of the complications. Currently, only symtomatic treatment is available. For example, people can treat the symptoms by using analgesics for pain, and antibiotics for infection, but these approaches do not arrest the sickling phenomena.
There remains, therefore, a very real and substantial need for a method of minimizing the adverse consequences of sickle cell anemia through resisting sickle cell crises in an individual who has this abnormality.